Apparatus for heat treating metallic bodies



Jan. 15, 1929.

E. ROMANELLI APPARATUS FOR HBA T TREATING METALLIC BODIES 2 Sheets-Sheet 1' Filed July 31, 1926 INVENTOR Humane/ll.

ATTORNEY Jan. 15, 1929. 1,698,824

E. ROMANELLI APPARATUS FOR HEAT IRIATIIG II'I'ALLIO BODIES F1106 Jilly 31, 1926 2 Sheets-Shut 8 FIGS.

\ 'I'NVENTOR EKomme/(l ATTORNEY Patented Jan. 15, 1929.

UNITED STATES PATENT, OFFICE.

EMILIO BOMANELLI, OF IBLOOMFIELD, NEW JERSEY, ASSIGNOR T WESTINGHOUSE LAMP COMPANY, A CORPORATION OF PENNSYLVANIA.

Application filed July 31,

This invention relates to a method and apparatus for treating metallic bodies and more particularly to the heat treatment of tungsten bodies employed in the manufacture of incandescent electric lamp filament.

The process of producing electric incandes: cent lamp filament includes the formation of bodies, termed slugs, which are produced by compressing the tungsten powder until the particles adhere and take the form desired, usually of elongated or bar shape.

These slugs are then subjected to a heat treatment for the purpose of sintermg the particles of tungsten together preparatory'to a swaging and drawing operation in the production of a lamp filament. The present 1nventi0n is particularly concerned with the heat treatment or sintering of the compressed tungsten bodies.

ll eretofore, when a slug was to be subjected to a sintering operation it was the practice to grip each end of the slug by means of a pair of clamps. Electrical energy was then passed through the slug to raise the temperature thereof sufficient to obtain a sintering of the particles of tungsten and produce a compact homogeneous body. This manner of treatment, however, resulted in a conduction of heat from the ends of the slugs by reason of the clamps. This transfer of heat from the slug prevented a complete sintermg action of such portions of the slug as were embraced by the clamps. It was, therefore, necessary to remove the incompletely sintered ends before subjecting the slug to the swaging and drawing operations, and a conslderable loss in material resulted. This loss was not only undesirable from an economic standpoint, but also made it necessary to rehandle the slug for the removal of the improperly treated ends.

An object of the present invention is, therefore, to provide a method and apparatus for the more economic and convenient heat treatment of metallic bodies and to provide means for supporting a plurality of bodies during a sintering operation and to effect an automatic release of the bodies during said operation. so In accomplishing the above I, provide a mercury cup for receiving one end of a slug,

which has been previously sintered. T o the. exposed end of the sintered slug another un- 1926. Serial No. 126,126.

slntercd slug is clamped; the two slug ends lapping each other to a width equal to the width of a slug. The upper end of the unsintered slug is secured in a spring clamp and the lapped ends of the sintered and un sintered slugs are secured between clamps which are held closed by means of a toggle oint. Electric energy is then passed through the slugs and as the unsintered slug beconies sintered it shrinks and raises the lower slug 1n the mercury cup. This shrinking action of the slug is utilized to actuate certain 1ncchanical elements, which release the clamps holding the lapped ends of the slugs. This releasing action is made to occur at the proper period so that the lower slug adheres to the upper slug and the lapped ends which were previously held by the clamp obtain the full benefit of the heating current and are completely sintered.

The upper end of the slug, which was held in the spring clamp, will obviously not have been completely sintered. In the next treatment, however, the upper slug is made the lower slug and the end thereof, which has been held by the clamps and is completelv sintered in position in the mercury, and the uncompletely sintered slug is held between the clamps and completely sintered. upon the removal of the clamps. Thus the slugs may be fully sintered from end to end without any loss or waste.

The invention will be more fully, understood by reference to the accompanying drawings in which Figure l is a plan view, partly broken away, of an apparatus embodying the present invention.

Figure 2 is a front elevational view of the apparatus shown in Figure 1. Figure 3 is a side view in elevation of the apparatus shown in Figure 2, but including the upper clamp for securing a slug; Figure 4 is a fragmen tary detail view partly in section and shows mechanism for actuating a pair of jaws, and Figure 5 is a perspective view of a trip member for operating a pair of clamp jaws.

In the present embodiment of the invention a mercury cup is suitably supported on and extends below a table or bed plate 11. Disposed at opposite sides of the mercury cup are tubular ide members 12 and 13, the

lower ends o which may be suitably secured in the bed plate 11. Each guide is provided with an internal conductor 14, through which.

. a cooling liquid may pass into the upper end of the guide and downwardly along theinterior surface thereof to maintain the guide at a suitably low temperature. Each guide is providedwith a slidable carrier 15 which is secured to a plate 16 by bolts 17, passing through lugs 18 on the carriers and through jaw members of oppositely disposedpairs of jaws, said pairs bein indicated as a whole by the numeral 19,-tl1e bolts 17 serving as pivot points for the jaws. One pair of jaws is disposed on each side of the mercury cup, and a description of one pair will serve for both.

The jaws are preferably made flexible so that they may give slightly and firmly grip the objects to be secured thereby.

Each jaw comprises a pair of oppositely disposed lever members 21 and 22, connected at their upper ends by cross-pieces or contact members 23. The lower ends 24 of the jaws are connected by toggles 25, the links of which arepivoted at 26 on pins 27 secured in a movable portion 30 of the carrier 15, the function ofwhich will be later described. The pins 27 project into slots 28 1n the plates 16. The toggles 25 may be constructed in the usual manner of the pair of links, link 29 being, however, extended and provided with a hand lever 31. This hand lever as shown in Figure 1 is of bow shape and extends around the mercury cup and is connected to a link of each of the'toggles so that an upward movement of the hand lever may be effected to either break the toggles and open the jaws by separating the contact members 23 or a downward movement of the hand lever will operate to straighten the toggles and close the jaws.

The mechanism so far described takes care of the manual operation of the device to open or close the jaws and it will thus be evident that a sintered tungsten slug 32 may be lapped at 33 with an unsintered tungsten slug 34 and secured by thejaws.

The upper end of the unsintered be secured by jaws 35 and 36, jaw 35 be ng urged toward the jaw 36 by reason of a spring member 37 carried on a' projection 38 at the end of an upright 39. .Electrical energy may be passed through the upright thence .through the tungsten slugs by suitable conductors 30 and 30"ithe mercury 31 in which the lower slug 32 is disposed acting as the lower contact.

As above mentioned, the present method of, treating or sintering tungsten bodies includes the use of a sintered body in connection with a unsintered body and when. two such bodies are clamped together and the sintering current passed therethrough the unsintered body becomes attached to the clamps, holding the lapped ends of the slugs may be removed by an actuation of within the slug may the sintered body. and

the hand-lever 31. It is desirable, however, to automatically effect a release of the clamps and for this purpose I utilize the shrinking which occurs during the sintering of a heat treated body. 7

The automatic actuation of the pairs'of clamping j awsjl-Q is attained by providing the carriers 15 withlhe'movable ends or collars" 30 in which pins 27 of the toggles are secured. These ends or -collars are normally urged downwardly by helical springs 42, disposed carriers 15 thus the action is to open the jaws.

When a pair of slugs is secured by the jaws a movement of the lever 31 causes the links of the toggles to become engaged by latch members 43, pivoted at 44 on the main por-' 'tion of the carrier 15. The latch members 43 are somewhat similar in (see Fig. 5) but are constructed to embrace the carrier members '15. Ends 45. of the latch members are disposed above projections 46 integral with the carrier members 15 and springs 47 act to normally position the latch members for engagement with the toggles.

When the slug 34 shrinks the entire jaw operating mechanism moves upwardly until the ends 45 of the latch members engage the stops 48 suitably positioned on posts 49.

When the latch members engage the stops the jaws will move from engagement with the lapped ends of the slugs.- The slugs form to bell cranks ing tungsten filament wire is greatly simplitied and a decided advance step is attained in the art. If desirable, suitable' means may be provided within the mercury cup to compensate for the weight of the slugs as it sinters as well as the weight of the clamps.

This may be obtained by suitable springs or V floats within the mercury well.

Although a preferred embodiment of the invention is shown described herein, it is to be understood that modifications may be made therein without departing from in the appended claims,

l/Vhat is claimed is: A

1. A machine for supporting metallic bars during a heat treatment which comprises gripping means for securing a plurality of bars, means for heating the bars to join them together, means for releasing the gripping the I spirit and scope of the invention asset forth 'means' after 1a predetermined stage in the 1 heat treatment suflicient to join said bars and means for continuing the heat treatment.

2. A device for sintering slugs of -com-[ pressed metallic powder which comprises means for securing an end of one slug, gripping means for securing the opposite end of said slug in contact with an end of another "slug, means for passing an electric sintermg current through said-slugs, means for releasing said gripping members after a given del gree of sintering has occurred said current operating to permit a complete sintering action of at least one slug.

3. A device for sintering bodies formed of compressed metallic powder by the passage of .an electrical current therethrough which comprises means for holding one body,

jaws for holding another bodyin contact with the said first mentioned body, means for passing a sintering current through said bodies until they become joined through the said sintering -action, means for actuating said jaws after said bodies have become olned and means for completing the smtermg of one of said bodies. g

4. A device of the class described comprisinga clamp. for holding a body, a mercurypool, gripping members for holding another ody with one end in said pool and the other end in contact with said first mentioned body, means for holding the gripping members closed and means for releasing said members upon a contraction of at least one of said bodies.

i 5. A device of the class described comprising a clamp for holding a body, amercury pool, gripping members for holding another body with one endin said pool and the other end in contact with said first mentloned body, a latch for holding the gripping members closed and means for automatically actuating said latch to release said members upon a contraction of at least one of said bodies.

6. A device of the class described,comprising a clamp for holding a body, and an electrical conductive medium, gripping jaws for holding an end of a second body in lapped contact with said first mentioned bod said second body having an end disposed in said medium, a toggle member for holding said jaws closed, means for passlng an electrical sintering current. through said bodies to toggle to open said jaws after said jaws closed, means for passing an electricalsintering current through said bodies to sinter the same and join the contacting surfaces thereof and means for breakin said toggle to open said jaws after said dies have become joined, said-current operating to completely sinter at least one of said bodies.

8. A device for heat treating bodies comthereof, jaw members or holding an end of another body in overlapped relation to an end of said supported body, .means for heat treating said bodies, and means for auto-- matically actuating said jaw members after gree, said heat treating means operating to continue the heat treatment of said bodies.

9. A device for heat treating bodies comprising means for grip ing a body at an end thereof, jaw members For holding an end of another body in overlapped relation to an end of said supported body, means for heat treating saidbodies, and means'controlled b prising means for grip ing a body at anend heating said bodies to a predetermined dea predetermined change in the physical d1- mensions of'said bodies through heat treatment to actuate said jaw members to releasev the overlapped ends. of said bodies, said heat treating means operating to continue the heat treatment.

'10. A'device for supporting a pair ofbars I.

during-a heat treating operation comprising gripping means for holding ends of said bars in overlapping relation, means for securing the free end of one of said bars, means for heat treating said bars and means whereby a change in the dimension of at'least one of said bars actuates said gripping means to release the bars, said heat treating means operating to continue the heat treatment.

In testimony whereof, I have hereunto subscribed my name this 30th dayof J uly,'1926.

ammov ROMANELLI. 

